Grinding machine



March 21, 1933. Q W NELSON 1,902,661

GRINDING MACHINE Filed NOV. 6, 1950 I 7 4 ammwmww//m nl mm 011/. lylahf.

m afg/M Patented Mar. 21, 1933 UNITED STATES oscAn W. NELSON,or'ronrilnnn'onneonf GRINMNG MACHINE Application led November 6, 1930.Serial No. 493,879.l i

The invention relates Vto grinding machines, and has for its principalobject the provision of a grinding machine adapted for extremely finework, such for instance as pointing pivots used in watches, clocks, and`delicate instruments.

A further object of the invention is the provision of a portablegrinding machine adapted to be supported in an operative po- 1o sitionmanually and to be connected to a driving shaft by means of an elasticbelt to permit of operation of the machine in various positions, andadapt the grinding disk to be driven in either direction.

The invention will be described in detail hereinafter and will be foundillustrated in the accompanying drawing, in which Figure 1 is a view inelevation of the improved grinding machine showing it geared 2o to adriving shaft of a conventional motor,

Figure 2 is a longitudinal sectional view of the grinding machine, and

Figures 3 and 4 are transverse sectional views on planes indicated bythe lines 3-3 and 4 4, respectively, of F1 ure 2.

In the drawing similar re erence characters are used to designatecorresponding parts throughout the several views.

As shown in the drawing the grinding machine comprises a handle 1 thatis preferably enlarged at one end as shown at 2 to give stability to themachine and to eliminate vibration when in operation. Secured in thehandle 1 that is preferably made of fibrous V material such as wood, orthe like, is a bushing 3 of a suitable metal having longitudinal andpointed ribs or spines 4 that enga e in the fibers of the handle to holdthe bushing in position. Bushing 3 is provided with 4o a tubular bore 5that extends from the smally 'er end of the handle 1 inwardly of thehandle, but ends short of the'inner end of the bushing, and the innerend of the bushing is provided with a reduced polygonal bore 6. 7lindicates a shaft or arbor inserted in the bore 5 and having` a reducedand Spolygonal end 8 that engages in the bore 46," the angles of saidreduced portion 8 being yprovided Withthreads 9to receive a cap nut 10to hold the shaft or arbor in position in the vbushy ing, the bushing' 3endinglshort of the larger end of` the handle 2 to provide for receptionof the cap nut 10, as best shown`in-Figure2.

The other endof the shaft or arbor 7 is provided with a flanged head 11.12 indi- 55 cates a sleeve mounted on the shaft or arbor 7 and rotatableon said shaft, said sleeve 12 bein provided with a flange 13 engagingthe anged head 11, and the sleeve 12 .is eX- teriorly threaded as shownat 14. 15 desig- 60 nates a grinding disk having a metal hub 16 that issplined as shown at 17 on the sleeve 12. A pulley 18 is also mounted onthe sleeve 12 and is preferably formed with a ,A hub 19 and flanges 20and 21 secured thereto 65 in any suitable manner. The outer face ofv theiiange 21 and the corresponding face of the hub 19 has a washer 22 ofrubber or other friction material secured thereto by means v of acircumferentialoutwardly directed returned flange 23 on said flange 21,that when in position as shown best in Figure 2 engages the hub 16frictionally so that the grinding disk 15 is rotated simultaneously withthe pulley 18. 24 designates a jam 75 nut mounted on the sleeve 12 tohold the pulley 18 in frictional engagement with the hub 16 as abovestated.

25 designates a belt trainedv on pulley 18 and gearing the pulley to theshaft 26. In,80 Figure 1 the shaft 26 is shown as the driving shaft of amotor 27 but it will be apparent that any other source of power may-besub. stituted for a motor shaft, and the arrange- 35v ment shown in thedrawing is for illustration only.

' In use, the grinding machine being geared to a suitable shaft 26 isheld in the hand and obviously is suitable for very delicate work 9oflanged head engaging the head onthe shaft,

and particularly for finishing gear pivots in Watches, clocks, anddelicate instruments.

28 and 29 designate anti-friction bearings, bearing 28 being mounted ina recess 30 in the flanged end of the sleeve l2, and bearing 29 beingmounted between the end of the bushing 3 and the sleeve 12, said bearingbeing arranged to relieve the thrust on the ends of the sleeve 12.

What is claimed is A portable grinding machine, comprising a shafthaving a flanged head at one end, the other end ofthe .shaft beingreduced and polygonal in cross section, a handle having .a longitudinalbore therethrough, ay sleeve secured in said bore and providedfwith abore to receive the shaft, a threaded sleeve rotatably mounted on theVshaft and having a a grinding disk splined on the threaded sleeve andabutting the head thereon, a pulley loosely mounted on the sleeve, afriction Washer secured to the pulley and engaging the grinding disk,and a jam-nut threaded on the threaded sleeve and engaging the pulley tohold it for rotation with lthegrindng disk and threaded sleeve, saidpulley being adapted to be geared to a motor shaft. v

In testimony whereof I alix my signature.

' OSCAR W. NELSON.

